We previously reported preliminary findings that unbound, bacteria derived glucosyltransferase (GTF) and fructosyltransferase activites could be measured in human saliva. The levels of enzyme activites were related to the amounts of S. mutans present in the saliva from different human subjects. Further studies with salivas from different human subjects have corroborated these results. Recent experiments showed that a new two-hour saliva pellicle acquired by human teeth in vivo also formed glucan/frucan polymers from sucrose. In vitro studies showed that GTF from S. mutans adsorbed to saliva-coated hydroxylapatite and to several different chromatographic media with different physico-chemical surfaces. In all instances the GTF was catalytically active in the adsorbed state. In other experiments, the greatly reduced attachment of S. mutans to saliva coated surfaces was overcome when the bacteria were allowed to grow and form glucan in the presence of sucrose. These results suggest that GTF adsorbed to hard surfaces (eg. teeth) may be an important mechanism by which S. mutans can attach to such surfaces. GTF has been purified to a specific activity of 19.6 IU/mg protein. GTF fractions that make water-soluble glucans and water-insoluble glucans were found to contain 26% and 23% acidic amino acids; 7.1% and 7.4% basic amino acids; and 39.1% and 39.6% hydrophobic amino acids. Continued experiments to obtain GTF in homogenous form for vaccine studies are in progress.